This is a lever for string trimmers. This particular lever is used to control the amount of line that is fed from the auto-feed spool on the trimmer. This part has a tendency to wear out due to normal wear and tear. It's always a good idea to have an extra one on hand because of this. This part can easily come into physical impact with hard objects while trimming. The black plastic material that it is made out of can crack and break if the force is excessive. If this happens, it will need to be replaced. The operator should never place his or her hands near this component while the machine is operating.This component is an OEM part sourced directly from the manufacturer. It is sold individually. This specific lever is compatible with electric string trimmers that are manufactured by Black + Decker.